Southern Resident orca population dwindles to a 30-year low

Pictured are J36 and J52 (male calf, 03/30/2015) from the southern resident killer whale community. Wikipedia summary: “The smallest of four resident communities within the Northwestern portion of North America Pacific Ocean. It is the only killer whale population listed as endangered by the U.S. Fish & Wildlife Service.” (Photo courtesy of the Center for Whale Research)

Pictured are J36 and J52 (male calf, 03/30/2015) from the southern resident killer whale community. Wikipedia summary: “The smallest of four resident communities within the Northwestern portion of North

Pictured are J36 and J52 (male calf, 03/30/2015) from the southern resident killer whale community. Wikipedia summary: “The smallest of four resident communities within the Northwestern portion of North America Pacific Ocean. It is the only killer whale population listed as endangered by the U.S. Fish & Wildlife Service.” (Photo courtesy of the Center for Whale Research)

Pictured are J36 and J52 (male calf, 03/30/2015) from the southern resident killer whale community. Wikipedia summary: “The smallest of four resident communities within the Northwestern portion of North

Their primary food source is dying off; the Trans Mountain Pipeline is expanding, which will increase the number of tankers trucking through the orcas' habitat by seven times, among other exposure risks like noise and spills.

And now comes the latest spot of bad news: For the last three years not one calf has been born to the shrinking pods of the black-and-white killer whales in the Pacific Northwest, resulting in a 30-year low in orca population.

The annual census of Puget Sound's resident orcas found that just 75 killer whales, across the three Southern Resident pods (J, K, and L), are still swimming through the Pacific Northwest waters. The J pod has 23 members, while K has 18, and L has 34.

In addition to finding no new births of Southern Residents, the census reported two missing and presumed dead members, 23-year-old Crewser (also known as L-92), and a 2-year-old calf named Sonic (J-52).

Southern Resident facts

--Southern Residents were listed as an endangered species in 2005, thanks to too many deaths and too few births.

--In the late 1990s, after orca capture became illegal in 1989, there were almost 100 whales in the population. But that trend has not continued.

--They migrate in the Salish Sea to the northern coast of British Columbia, surfacing in the south at Puget Sound (when we're lucky).

--Their route follows the migration pattern of king salmon, their primary prey, and has grown more unpredictable as their food supply has gotten more erratic.

--Males weigh up to 22,000 pounds, and live up to 30 years. Females have gone as high as 16,000 pounds, and can anywhere up to 60 years old. (Although there was one member of the J-pod who lived to 105.)

--2015 saw a "baby boom" throughout the year, with nine new orcas being born. Three of them -- including Sonic -- have since died.

The cause of the dwindling supply? More of the same, according to many researchers who study the orca pod. Pollution, both old and new, accumulates in their primary prey, and gets stored in the fat on the orca, surpressing the immune system and making the whales more susceptible to disease.

Plus that prey, Chinook salmon (also known as king salmon), are not as big or plentiful as they once were.

"In 2017 -- a very poor year for Chinook -- and we're in the core area here where they used to feed almost daily," Ken Balcomb, a founder and senior scientist at the Center for Whale Research, said in video a last year. "We've seen the twice, three times this year.

"And the salmon (they do find) are smaller, much less numerous, and they are virtually all hatchery fish."

"It's also essentially a big rock ditch where sound bounces off. When you add in commercial vessel traffic going to Vancouver, recreational boaters and whale watching operations, it's a pretty noisy place," Brad Hanson, team leader for recovery efforts for the Northwest Fisheries Science Center, said to The New York Times.

RELATED: Northwest "icons" that could be threatened with Trump's Endangered Species Act changes:

Endangered species

Orcas (killer whales): Four babies were born this winter to the southern resident population of orcas (killer whales). But the great marine mammals remain listed as endangered due to the decline of the orcas' major food source -- chinook salmon. Chemical contamination poses a threat.

A much greater danger looms. Expansion of a pipeline from Alberta to Burnaby, a suburb of Vancouver, could bring hundreds more oil tankers into inland waters. Canada is unprepared for a major (or minor) oil spill off southern Vancouver Island and in the Gulf Islands. B.C. and Canadian governments are panting to bring the carbon economy to the West Coast.

Orcas (killer whales): Four babies were born this winter to the southern resident population of orcas (killer whales). But the great marine mammals remain listed as endangered due to the decline of the orcas' major food source -- chinook salmon. Chemical contamination poses a threat.

A much greater danger looms. Expansion of a pipeline from Alberta to Burnaby, a suburb of Vancouver, could bring hundreds more oil tankers into inland waters. Canada is unprepared for a major (or minor) oil spill off southern Vancouver Island and in the Gulf Islands. B.C. and Canadian governments are panting to bring the carbon economy to the West Coast.

Since orca bodies aren't generally recovered -- frequently sinking and becoming part of the ecosystem, or washing up on remote beaches -- researchers can't be sure what's behind the increase in deaths of the population. It could be a disease outbreak that the stress of their environment has made them more susceptible to, or it could be representative of a greater problem with the ecosystem, which has been warmed as much as six degrees above normal in some areas along the Pacific coast.

Steps are being taken: In March, Gov. Jay Inslee issued an executive order directing the state agencies to do more, and two months later he convened a task force of state, tribal, provincial and federal officials to think of some solutions.

"The orca will not survive unless all of us in the state of Washington somehow make a commitment to their survival," Inslee said, when he signed the order. "The impacts of letting these two species disappear would be felt for generations."

His approach includes calls for more salmon, quieter boat traffic, clean up of toxics in the water, and reducing the number of oil spills.

In short, the Southern Resident population won't be going down without a fight. But some researchers say that there's going to have to be a commitment to saving the animals from more places than one.

"It's an ecosystem-wide problem," Hanson said. "Things are out of whack and we have to get them back to where we can sustain killer whales. And the clock is ticking."

SeattlePI reporter Zosha Millman can be reached at zoshamillman@seattlepi.com. Follow Zosha on Twitter at @zosham. Find more from Zosha here on her author page.